Projected rotational (upper panel) and extra line-broadening velocities (lower panel) for the OB sample as a function of T_eff. O and B supergiants are highlighted in dark blue and red, respectively, and O giants and dwarfs in light blue. Intermediate- and fast-rotating stars (vsini ≥ 110 km s^-1) are additionally marked by large circles (for more information and arrows see Sect. 5.2).